British No 2 Johanna Konta was soundly beaten by sixth seed Kurumi Nara in the opening round of the Istanbul Cup.
The 23-year-old had not dropped a set in five previous meetings with her Japanese opponent but the match slipped away from her very quickly as she slumped to a 6-2 6-0 loss.
Konta, who is at a career-high ranking of 89, had won two qualifying matches to make the main draw in Turkey.
Also on Tuesday, top seed Caroline Wozniacki gave a lesson to teenager Belinda Bencic in her opening match.
Swiss Bencic is one of the most exciting prospects in the women's game but top seed Wozniacki needed just 44 minutes to win 6-0 6-0.
Bencic, 17, won only nine points on serve in the whole match, and none on second serve, with Wozniacki progressing to meet Italy's Karin Knapp in round two.
Second seed Roberta Vinci was only slightly less convincing in beating Anna Tatishvili 6-2 6-2 but fifth seed Magdalena Rybarikova was upset by 16-year-old qualifier Ana Konjuh.
The Croat demonstrated her potential in reaching the third round of Wimbledon and came from a set down on Tuesday to defeat Rybarikova 3-6 6-3 6-4.
Eighth seed Karolina Pliskova saw off local wildcard Cagla Buyukakcay 6-4 3-6 6-0.
Former French Open champion Francesca Schiavone was a 6-2 6-3 winner over Jovana Jaksic and there were also first-round wins for Shahar Peer, Kristina Mladenovic, Misaki Doi, Stefanie Voegele, Katerina Siniakova and Alexandra Dulgheru.